Contribution of geoelectrical soundings and pedological wells to the estimation of the tonnage of lateritic gravels of the northern flank of Mount Bangou: implications for road construction

摘要

The increasing demands on lateritic gravels in road construction presently make it necessary to quantify the available resources that can be used in road construction. This study aims to estimate the tonnage and to valorize the lateritic gravels of the north flank of Mount Bangou (west Cameroon) in road construction. Interpretation of 48 vertical electrical soundings coupled with 20 pedological wells from five lateritic gravel sites was carried out to determine the thickness of the lateritic gravel level. The thickness of the lateritic gravel level obtained from the geoelectrical soundings is the greatest (8.88-12.45 m) compared to that obtained from the pedological wells (1.23-1.98 m), and thus shows the inadequacy of the pedological wells for the determination of the thickness of the lateritic gravels. Thus, the electrical resistivity method is appropriate to estimate the thickness of the lateritic gravel level. The lateritic gravels studied are characterized by the electrical resistivity curves of type K, HK, Q, QH, KQ, HKH, H, and KH. The medium-thick (8-36 m) and thick (13-44 m) zones are areas of high potential lateritic gravels. The proven reserves of lateritic gravels at the Chenye, Sekakouo, Bamendjou 1, Bamendjou 2, and Bangam sites are, respectively, 3,479,003 t, 1,389,522 t, 5,002,505 t, 839,455 t, and 2,663,105 t and can build, respectively, 53,298 m; 226,167 m; 131,574 m; 778,314 m and 401,068 m of road, either as a subgrade layer or sub-base layer.